It has long been recognized that electrical current will induce a magnetic field, and that a moving magnetic field can induce current, or changes in the magnitude of a pre-existing current. One conventional application of this phenomenon is the transducer for converting between current and vibration. More particularly, a transducer for converting between vibration and current can: (1) convert linear mechanical vibration (e.g., acoustic vibration) into a pattern of variations in electrical current; and/or (2) convert variations in a current into vibration. Such a transducer can be used to produce electrical signals from the vibrations of a musical instrument, such as a guitar.
In a guitar, taut strings are vibrated to induce acoustic vibrations in the guitar body and the air surrounding the guitar. A transducer is fixed to some part of the guitar. The vibrations of the guitar induce relative vibration between a coil and a permanent magnet in the transducer. This induced relative vibration causes current patterns in the coil. The current in the coil is usually amplified and sent to a speaker to produce louder and better-directed sound corresponding to the vibration of the guitar.
A variety of transducers have been used to convert the vibrations of a guitar into electrical current patterns. One common type involves the use of one or more piezoelectric crystals. However, such transducers suffer from a number of known drawbacks. One drawback is that piezocrystals typically require an outside power source a baseline current to operate effectively. In addition, piezocrystals tend to produce an unattractive sound distortion that is especially problematic when amplified.
Some guitars, such as disclosed in U.S. Pat. No. 5,898,121, employ string sensors or pickups, which are disposed generally beneath the strings and are adapted to convert the vibrational energy from the strings into electrical signals that can be amplified. Other guitars, such as disclosed in U.S. Pat. No. 3,624,264, use body sensors attached to the guitar soundboard to translate the motion of the soundboard into electrical signals. However, none of these guitars employ a plurality of sensors connected in series for picking up vibrational energy at different locations on the guitar and converting the combined vibrational energy into electrical signals.
In view of the above, there exists a need for a musical instrument including an array of sensors connected in series for picking up vibrational energy at different locations on the musical instrument and converting the combined vibrational energy into electrical signals for amplification. In addition, it would be desirable that the musical instrument employ sensors that do not produce distorted sounds like those associated with the use of piezocrystals.